i have a 1995 F150 with the 4.9L. i am looking to remove the secondary air but not totally sure how to do so. i mean i understand pull the pump the diverter valves all the lines etc but where the secondary air injection tube goes into the head im not sure how to close those off i cant seem to find any threads that talk about it if anyone has any advice please reply.

 

I would assume ford used the same system that they used on their small blocks. If thats the case, once you get the injection-tube off, there are 5/8"-11 threads machined into the head. You just need to go to the hardware store and buy the shortest 5/8"-11 bolt you can find and plug up the port with it.

 

On my trucks, I cut those pipes off going into the head. Then bent them over to seal off the pipe before going into the head. I did that as I rounded a few of those nuts off even after a week long soak with PB blaster. I only had 2 of them requiring extra squeeze to seal them back up. Use a good pair of vise grips to bend and squeeze shut.

After 10 years I had no further issues. Besides the ECU complaining of the secondary air is inop(no preformance issues).

 

In a OBD1 the computer won't know that the air is working or not exactly because it has no electrical connection to the computer, the pump and plumbing is all mechanical and dumps into the exhaust after the only 1 oxygen sensor on the 4.9 91 f 150.